8888
C. Gremmen et al. / Tetrahedron Letters 42 (2001) 8885–8888
ammonia 85:10:5) yielded (R)-(+)-salsolidine 2 in 92%
(ee >98%), [h]D=+56.0.
(c) Zio´lkowski, M.; Czarnocki, Z. Tetrahedron Lett. 2000,
41, 1963; (d) Cabedo, N.; Andrebu, I.; Ram´ırez de Arel-
lano, M. C.; Chagraoui, A.; Serrano, A.; Bermejo, A.;
Protais, P.; Cortes, D. J. Med. Chem. 2001, 44, 1794.
7. (a) Cox, E. D.; Cook, J. M. J. Org. Chem. 1995, 60, 1797;
(b) Silveira, C. C.; Bernardi, C. R.; Braga, A. L.; Kauf-
man, T. S. Tetrahedron Lett. 1999, 40, 4969; (c) Comins,
D. L.; Thakker, P. M.; Baevsky, M. F.; Badawi, M. M.
Tetrahedron 1997, 53, 16327.
8. (a) Soe, T.; Kawate, T.; Fukui, N.; Hino, T.; Nakagawa,
M. Heterocycles 1996, 42, 347; (b) Kawate, T.;
Yamanaka, M.; Nakagawa, M. Heterocycles 1999, 50,
1033; (c) Waldmann, H.; Schmidt, G.; Henke, H.;
Burkard, M. Angew. Chem., Int. Ed. Engl. 1995, 34, 2402;
(d) Kawate, T.; Yamada, H.; Soe, T.; Nakagawa, M.
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In summary, the use of the p-tolylsulfinyl chiral auxil-
iary provided a practical enantioselective route to tetra-
hydroisoquinolines with alkyl and benzyl substituents.
Separation of the diastereomers and removal of the
N-sulfinyl group under mild conditions without racem-
ization yielded a range of enantiopure tetrahydro iso-
quinolines. This procedure allows the efficient synthesis
of biologically relevant enantiopure alkaloids such as
(R)-(+)- and (S)-(−)-salsolidine.
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